1. Field of the Invention
This invention relates generally to analog-to-digital conversion devices and more particularly to apparatus for providing a representation of an electrical signal voltage by a group of binary signals that are determined by approximating the analog signal with a predetermined number of decreasing voltage levels.
2. Description of the Related Art
It is known in the related art to approximate a signal having an arbitrary potential by a multiplicity of binary states. The digitalization of the signal has the advantage of permitting convenient manipulation and transmission without the necessity of maintaining the original potential level. The approximation is typically accomplished by providing that the analog signal level is within certain boundaries, and providing that a sequence of binary states specify the absence or presence of an amplitude component in a sequence of components with decreasing amplitude. A typical example can occur where, beginning with an arbitrary amplitude, each successive binary state represents a magnitude one-half of the magnitude represented by the previous binary quantity. An approximation of the original signal can be reconstructed from the multiplicity of binary states by means of a digital to analog converter, wherein each binary state is electrically summed to provide a reconstruction of the original signal level.
The instant invention relates to the method of providing the multiplicity of binary states by testing the inclusion of each decreasing amplitude component against the original signal. If the partially reconstructed signal is tested to be less than the original signal, then the component under test is included in the group of binary states. If the reconstructed signal is greater than the original signal, the component most recently tested is not used and the next smaller amplitude component is tested. In this manner, the original signal can be approximated to a accuracy limited only by the number of binary quantities available and the error margins of the testing apparatus.